Issue 68

A. Aabid et alii, Frattura ed Integrità Strutturale, 68 (2024) 209-221; DOI: 10.3221/IGF-ESIS.69.14

F INITE ELEMENT (FE) METHOD

T

he ANSYS commercial software with APDL was used with the coding method. The present work simplified the fracture mechanics parameters through the FE method. In fracture mechanics, the study of failure structures concerning their material can play a key role in the elastic region and therefore this work is limited to LEFM because the thin plate was used. Crack Tip Modeling In crack tip displacement analysis (Fig. 3), there is a high-stress gradient needed in the region around the crack tip to measure SIF and because of this, the FE modeling required more attention in this specific region. This can be solved by both two dimensional and three-dimensional modeling and the terminology used for the crack tip with representation around the crack region is slightly different. To define the crack tip for a 3D model, it should be considered as a crack front.

Figure 3: Illustration of the crack tip and crack front for the present FE model

Singular elements suggested by Barsoum, [34] which is utilized to find a reasonable sign of the crack tip displacement. For LEFM problems, near the crack front, the displacement varies as r , where r is the distance from the crack tip. At the crack end, the stress and pressure are special, changing as 1 r . Using the KCALC command, the stress intensity at the crack for a linear elastic analysis is computed. The study fits nodal displacement near the crack and location procedure [35],

2G V 1 k r 

K 2 π 

(1)

I

For the others, where V is the face split motion. The final term of the Eqn. (1) factor V r , which must be assessed and proven on nodal displacement and locations. V normalizes so that V is 0 at node I (r = 0). Then A and B determined so that,

V

 

(2)

A Br

r

at point J and K. Next, let r approaches 0, then it becomes,

r 0 V lim A r  

(3)

thus Eqn. (1) becomes,

2GA 1 k 

K 2 π 

(4)

I

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